Home surveillance systems are incredibly expensive, but if you're looking for more of a DIY approach, Instructables user Scavix shows off how to build your own small-scale system for about $120 using a Raspberry Pi.

Scavix's system uses a Raspberry Pi, the Raspberry Pi camera module, some housing for that camera, and a few other smaller pieces. After some set up, the end result is a home security system that can detect motion, broadcast a live stream, and more. It's a surprisingly powerful system all things considered and it's cheap enough that you can set up a few of them if you like. Of course, if you're looking for something similar that's a bit easier to set up, we're fans of Ninja Blocks.